samples: added STeP mobilie kinematic simulation to illustrate a multicore sample

[uLipe]

I forgot to tag 🤦

@microbuilder PTAL.

[microbuilder]

@uLipe What version of Zephyr is this being built against, and what QEMU version are you using? For some reason, when I build and run via:

$ west build  -p always -b mps2_an521  modules/lib/step/samples/mobile_robot_kinematic_server
$ west build -t run
-- west build: running target run
[0/1] To exit from QEMU enter: 'CTRL+a, x'[QEMU] CPU: cortex-m33
qemu-system-arm: warning: nic lan9118.0 has no peer

rpmsg registered endpoint number: 0
*** Booting Zephyr OS build zephyr-v3.2.0-2456-g7c9d7922116c ***
uart:~$ rpmsg registered endpoint number: 0
*** Booting Zephyr OS build zephyr-v3.2.0-2456-g7c9d7922116c ***
[00:00:00.510,000] <dbg> proc_mgr: step_pm_register: Registering node/chain (handle 0, pri 0)
uart:~$ 

I can't enter anyting in the Zephyr shell, which is a first for me.

$ qemu-system-arm --version
QEMU emulator version 7.0.0 (v7.0.0-dirty)
Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers

$ git describe
zephyr-v3.2.0-2456-g7c9d7922116

[uLipe]

Just update the README.

[uLipe]

@microbuilder , depending on version of Zephyr it is necessary to send a request for the remote processor before wakeup, it is also happens on the rpmsg demo, and only for the QEMU targets, I moved the wakeup request position and it should work now regardless the zephyr version .